Lawn Mower

ABSTRACT

A lawn mower is provided wherein mowed grass can be simply discharged from a mower device to the inside of a grass collector, turnover of a traveling body can be simply prevented, and the mowed grass in the grass collector can be simply discharged to a container etc. The lawn mower comprises a mower device mounted on a traveling body provided with right and left rear wheels, a grass collector for collecting the grass mowed by the mower device, a discharge duct for discharging the mowed grass from the mower device to an inside of the grass collector, and a lift mechanism having right and left fixed masts for supporting on the traveling body the grass collector to be lifted up and down. The grass collector is lifted by the lift mechanism to discharge the mowed grass in the grass collector. The lift mechanism is disposed within a width in the right and left directions of the grass collector, the discharge duct is disposed between the right and left fixed masts, and the discharge duct and the grass collector are connected through between the right and left fixed masts.

TECHNICAL FIELD

The present invention relates to a lawn mower comprising a mower devicefor mowing lawn grass uprightly planted on the ground, and a grasscollector for collecting grass mowed by the mower device, and inparticular, relates to a lawn mower equipped with a grass collector tobe lifted up and down through a lift mechanism to a traveling body.

BACKGROUND ART

Conventionally, in general, a lawn mower comprises a mower device havinga rotary mowing blade and attached to a traveling body to be lifted upand down, a discharge duct having a tubular shape and extending backwardfrom the mower device, and a box-shaped grass collector communicatingwith the discharge duct, wherein the lawn mower continuously mows grass,etc. on the ground with the mower device, and the mowed grass such asthe lawn grass is discharged to the grass collector through thedischarge duct from the mower device.

In this case, the conventional lawn mowers have employed an arrangement,wherein the grass collector are supported at both sides thereof by rightand left booms provided on a traveling body, when the grass collectorbecomes full of mowed grass, the grass collector is lifted above acontainer or a loading space of a truck, etc. by raising distal ends ofthe right and left booms with proximal ends thereof as fulcrums, and themowed grass in the grass collector is discharged into the container orthe loading space of the truck, etc. (for example, see Patent Document1). Also, well-known to the person skilled in the art is an arrangementwherein right and left fixed masts are erected on a rear part of arunning vehicle, and a grass collector is supported to the fixed maststo be lifted up and down, and the mowed grass in the grass collector isdischarged into the container, etc. (for example, see Patent Document 2or 3).

-   [Patent Document 1] JP 2002-84850 A-   [Patent Document 2] JP 09-9759 A-   [Patent Document 3] JP 09-47134 A

DISCLOSURE OF THE INVENTION Problems to be solved by the Invention

By the way, in Patent Document 1, there is a problem that because theright and left booms and hydraulic cylinders which rotate the booms andlift up and down the grass collector are arranged in both outsides ofthe grass collector, the booms or the hydraulic cylinders and hydraulicpiping thereof, etc. collide with growing trees, fallen trees orobstructions such as stones, etc. on the ground to be damaged. Forexample, there is a problem that even when a width of the grasscollector is increased in the right and left directions thereof in orderto increase the volume thereof, the booms or the hydraulic cylinders andhydraulic piping thereof, etc. are disposed in the outsides of the rightand left traveling parts because a distance between the right and lefttraveling parts (such as rear wheels and traveling crawlers) cannot beincreased. On the other hand, upward increase of the grass collector inorder to increase the volume thereof allows the booms or the hydrauliccylinder and piping thereof, etc. to be disposed inside of the right andleft traveling parts. However, this makes it difficult to discharge themowed grass to an upper part of the grass collector, thereforeinhibiting effective use of the volume of the grass collector foraccommodation of the mowed grass.

Then, as described in Patent Document 2, masts are erected on atraveling body, a grass collector is supported by the masts, andthereby, a lift mechanism including the masts and the like can bedisposed within a right and left width of the grass collector, the grasscollector can be increased in the right and left directions and thevolume thereof can be increased. However, it is necessary that a forcedtransfer mechanism such as a thrower for transferring mowed grass from amower device to the grass collector is specially provided and isdisposed outside of the traveling body. Accordingly, there are problemsthat the width of the traveling body in the right and left directionsincreases, and a structure from the mower device to the grass collectorfor discharging the mowed grass cannot be simply configured.

Moreover, in Patent Document 1, when the grass collector full of themowed grass is lifted up, a moving trajectory of the grass collector dueto rotation of the booms forms an arc. Therefore, a center of gravity ofthe traveling body moves not only upward and downward but also backwardand forward, and the traveling body becomes unstable and is likely tooverturn, so that the mowed grass cannot be easily discharged into thecontainer or the loading space of the truck, etc. In particular, byensuring a moving space of the grass collector necessary for rotation ofthe booms, a reverse traveling distance of the traveling bodyapproaching the container, etc. cannot be shortened. Accordingly, thereis a problem that the traveling body cannot be prevented easily fromoverturning in places where the traveling body easily overturns, such ason a soft ground or a sloping ground, when the mowed grass in the grasscollector is discharged.

On the other hand, as described in Patent Document 3, by lifting a grasscollector from a position of the rear of the traveling body forcollecting grass, to a position for discharging mowed grassapproximately vertical to and above the position for collecting thegrass, a reverse traveling distance of the traveling body approachingthe container, etc. can be shortened more than that described in PatentDocument 1 in which the booms are rotated. However, there is a problemthat the mowed grass on a certain side (inside of the container which iscloser to the traveling body) tends to be discharged, and the mowedgrass in the central part of the container, etc. etc cannot bedischarged easily.

On the other hand, in Patent Document 1 or Patent Document 3, there is aproblem that when the traveling body is in a stopped state with theparking brake thereof on, a misoperation of a PTO operation body by anoperator, etc. may cause the mower device to be driven and to be damagedeven on a paved road surface. There is a problem that even when theoperator brakes the traveling parts and urgently stops the travelingbody while driving the mower device to cut the grass, the mower devicecontinues to be driven. There is a problem that even when the grasscollector is supported at a position except a position for collectingthe grass, the mower device is driven by an operation of the PTOoperation body. There is a problem that during driving of the mowerdevice, the grass collector may be lifted up and down by a lift up orlift down operation of the lift operation body. In other words, themisoperation by the operator leads to improper driving of the mowerdevice and improper lifting up and down of the grass collector, makingit impossible to improve drivability or operability of mowing grassoperation for the operator.

In addition, in Patent Document 1, because the grass collector issupported at distal ends of the right and left booms which are rotatedby right and left hydraulic lift cylinders, a high position of a fulcrumpoint of the right and left booms allows a lifting amount to be largereven using a short boom. However, when the grass collector is lowered inthe position for collecting the grass, the overall height of the lawnmower cannot be lowered. Also, because the right and left booms and theright and left hydraulic lift cylinders are disposed at both sides ofthe grass collector, there is a problem that manufacturing costs ofhydraulic related parts of the lift mechanism cannot be easily reduced.On the other hand, as described in Patent Document 2, in the case thatthe grass collector is hung through a wire rope from a winch at theupper end of the masts, the overall height of the body cannot be loweredenough when the grass collector is lifted down to the position forcollecting the grass. Thus, there is a problem that the center ofgravity of the traveling body during a collecting grass operation cannotbe lowered enough.

Also, an embodiment of Patent Document 1 has a structure in which acover is connected through a third arm of a fork end shape to a secondarm fixed to the grass collector, the first arm is connected to thesecond arm and the cover; the cover is openably and closably connectedto the grass collector, and cannot be easily removed from the grasscollector. And, in Patent Document 2, the mowed grass in the grasscollector falls backward and downward by a self weight by opening thecover to the grass collector while the grass collector is openedbackward and downward in a constant posture. In other words, in thestructure of Patent Document 1 or 2, there is a problem that the grasscollector of which the cover is removed cannot be easily utilized for adust collection operation for discharging pruned branches or dust.

An objective of the present invention is to provide a lawn mower capableof preventing damages caused by collision of a lift mechanism withobstacles such as trees or stones, increasing a right and left width ofa grass collector to increase a volume thereof, easily discharging mowedgrass from a mower device to the grass collector, preventing overturn ofthe traveling body simply, and in addition, discharging the mowed grassin the grass collector into a container, etc.

Means for Solving the Problems

In order to achieve the above described object, a lawn mower accordingto claim 1 comprises a mower device mounted on a traveling body providedwith right and left traveling parts, a grass collector for collectingmowed grass by the mower device, a discharge duct for discharging themowed grass from the mower device into the grass collector, and a liftmechanism having right and left fixed masts for supporting the grasscollector to the traveling body to be lifted up and down, the liftmechanism being configured to discharge the mowed grass in the grasscollector after lifting up the grass collector by the lift mechanism,wherein the lift mechanism is disposed within a width in a right andleft direction of the grass collector, the discharge duct is disposedbetween the right and left fixed masts, and the discharge duct and thegrass collector are connected through between the right and left fixedmasts.

As for an invention described in claim 2, in the lawn mower according toclaim 1, the lawn mower comprises the lift mechanism including: rightand left movable masts supported to the right and left fixed masts to belifted up and down; a lift frame body disposed to the movable masts tobe lifted up and down; and lift drive means for lifting up and down thelift frame body, wherein the lift drive means are disposed on a baseframe connected to the right and left fixed masts on an upside of thedischarge duct.

An invention described in claim 3, in the lawn mower according to claim2, is configured, wherein the lift drive means and the movable masts arecoupled to a first double speed mechanism, the movable masts and thelift frame body are coupled to a second double speed mechanism, themovable masts are lifted up and down respect to the fixed masts by thelift drive mechanism, and thereby, the lift frame body and the grasscollector are lifted up and down to the movable masts.

An invention described in claim 4, in the lawn mower according to claim2, is configured, wherein mast supporting bodies of the right and leftfixed masts are connected to a rear end of the body frame of thetraveling body, and at the same time, bottom ends of the right and leftfixed masts are connected to right and left axle frames of the travelingbody for attaching the right and left traveling parts.

As for an invention described in claim 5, in the lawn mower according toclaim 1 or 2, the lawn mower comprises a supporting leg body thatapproaches in a landing direction by upward movement of the grasscollector to a position for discharging the mowed grass, and gettingaway toward the ground by downward movement of the grass collecting bodyto a position for collecting the grass, and a locking mechanism thatlocks the supporting leg body in a landing position by upward movementof the grass collecting body to the position for discharging the mowedgrass of the grass collector, wherein the supporting leg body and thelocking mechanism are disposed in the bottom ends of the right and leftfixed masts.

An invention described in claim 6, in the lawn mower according to claim5, is configured, wherein the locking mechanism is configured to lockthe supporting leg body by further upward movement of the grasscollector after the supporting leg body approaches in the landingdirection by upward movement of the grass collector, and the supportingleg body is configured to get away from a landing surface by furtherdownward movement of the grass collector after the locking mechanismgets away from the supporting leg body by downward movement of the grasscollector.

As for an invention described in claim 7, in the lawn mower according toclaim 1, the lawn mower comprises a grass collector supported to thetraveling body through the lift drive means to be lifted up and down androtatably supported to the traveling body through dump drive means, abraking operation body for operating to brake a traveling part of thetraveling body, a lifting operation body for operating the lift drivemeans, and a rolling operation body for operating the dump drive means,wherein permission control means for detecting a braking operation ofthe braking operation body and permitting each operation of the liftingoperation body and the rolling operation body is provided.

As for an invention described in claim 8, in the lawn mower according toclaim 7, the lawn mower comprises a check control means in which oneoperation of the lifting operation body and rolling operation bodyrestricts the other operation thereof.

As for an invention described in claim 9, in the lawn mower according toclaim 1, the lawn mower comprises an engine stop mechanism for stoppingan engine mounted on the traveling body, a PTO operation body foroperating to drive or stop the mower device, a PTO detection means fordetecting an operation of the PTO operation body in order to drive themower device, and parking brake detecting means for detecting anoperation of a parking brake to be on in order to keep the travelingparts of the traveling body in a braked state, wherein the engine stopmechanism is configured to be actuated by a driving operation of themower device when operating the parking brake to be on.

As for an invention described in claim 10, in the lawn mower accordingto claim 1, the lawn mower comprises a hydraulic lift cylinder, as thelift drive means, having a piston rod that advances upward, wherein thelift cylinder is disposed between the right and left fixed masts, bothends of mast traction bodies are connected to the traveling body andmovable masts, the masts traction bodies are stretched through tip guidepulleys disposed at a tip end of the piston rod, both ends of lifttraction bodies are connected to the traveling body and a lift framebody, the lift traction bodies are stretched through movable guidepulleys disposed at top ends of the movable masts.

As for an invention described in claim 11, in the lawn mower accordingto claim 1, the grass collector comprises a grass collection main bodydisposed to the lift mechanism, a cover openably and closably disposedon a rear face side of the grass collector, wherein a bottom rear end ofthe grass collector is connected to a rear end of the lift frame bodyprojecting backward from the movable masts by a dump fulcrum shaft, thegrass collection main body is configured to rotate backward around thedump fulcrum shaft, and at the same time, a top front end of the coveris connected to a top rear end of the grass collector through apin-structured opening/closing fulcrum shaft capable of being attachedand removed by one-touch operation, the cover is configured to rotatebackward and upward around the opening/closing fulcrum shaft, and thecover is configured capable of being separated from the grass collectionmain body by removing the fulcrum shaft from the grass collection mainbody connected to the cover.

Effect of the Invention

According to the invention according to claim 1, a lawn mower comprisesa mower device mounted on a traveling body provided with right and lefttraveling parts, a grass collector for collecting mowed grass by themower device, a discharge duct for discharging the mowed grass from themower device into the grass collector, and a lift mechanism having rightand left fixed masts to support the grass collector to the travelingbody to be lifted up and down, the lift mechanism being configured tolift up the grass collector and discharge the mowed grass in the grasscollector, wherein the lift mechanism is disposed within a width ofright and left directions of the grass collector, the discharge duct isdisposed between the right and left fixed masts, and the discharge ductand the grass collector are connected through between the right and leftfixed masts. Therefore, the lift mechanism can be disposed in the widthin the right and left directions of the right and left traveling parts,and the lift mechanism is prevented from colliding with growing trees,fallen trees or obstructions such as stones on the ground and beingdamaged. And the right and left width of the grass collector can beincreased, and the volume thereof can be increased. Also, the grasscollector can be connected to the mower device by the discharge ductwhich is extended approximately linearly between the right and leftfixed masts, in the other words, in a vicinity of approximately a centerof the right and left width of the traveling body. Accordingly, incomparison with the conventional structure in which a transportmechanism to discharge the mowed grass from the mower device to thegrass collector is specifically provided in an outside of the travelingbody, the width in the right and left directions of the traveling bodycan be reduced, and the mowed grass can be discharged from the mowerdevice into the grass collector with a simple transport structure.

According to the invention according to claim 2, the lift mechanismcomprises right and left movable masts supported to the right and leftfixed masts to be lifted up and down, a lift frame body disposed to themovable masts to be lifted up and down, and lift drive means for liftingup or down the lift frame body, wherein the lift drive means disposed ona base frame connected to the right and left fixed masts above thedischarge duct. Therefore, as supporting means of the right and leftfixed masts and as supporting means of the lift drive means, the baseframe can be commonly used, and an assembling structure of the right andleft fixed mast and the lift drive means can be simply configured. Also,by the right and left fixed masts and the base frame, both right andleft sides and a top side of the discharge duct can be enclosed, and thedischarge duct and the grass collector can be simply connected.

According to the invention according to claim 3, the lift drive meansand the movable masts are connected by a first double speed mechanism,the movable masts and the lift frame body are connected by a seconddouble speed mechanism, the movable masts are lifted up and down to thefixed masts by the lift drive mechanism, and thereby, the lift framebody and the grass collector are lifted up and down to the movablemasts. Therefore, a lifting and lowering stroke of the movable masts canbe easily made twice as much as that of the lift drive means, and alifting and lowering stroke of the lift frame can be easily made twiceas much as that of the movable masts. That is to say, a height of thefixed masts and a height of the movable masts can be lower not to blockvisibility of an operator (backward visibility of the traveling body).Also, because a lifting and lowering stroke (lifting amount) of thegrass collector (lift frame body) can be easily made four times as muchas that of the lift drive means, the lift drive means are simplyconfigured by, for example, an inexpensive short-stroke light-weighthydraulic cylinder.

According to the invention according to claim 4, mast supporting bodiesof the right and left fixed masts are connected to the rear end of thebody frame of the traveling body, and at the same time, the bottom endsof the right and left fixed masts are connected to right and left axleframes, of the traveling body, for attaching the right and lefttraveling parts to. Therefore, by the right and left fixed masts,connection strength of the body frames and the right and left axleframes can be improved. Also, by the right and left axle frames,connection strength of the body frames and the right and left fixedmasts can be improved. That is to say, the right and left rear wheelsand the grass collection box can be supported with high rigidity.

According to the invention according to claim 5, a lawn mower comprisesa supporting leg body that approaches to a landing position by upwardmovement of the grass collector toward a position for discharging mowedgrass, and getting away toward the ground by downward movement of thegrass collector toward a position for collecting grass, and a lockingmechanism that locks the supporting leg body to the landing position byupward movement of the grass collector to the position for dischargingthe mowed grass of the grass collector, wherein the supporting leg bodyand the locking mechanism are disposed in the bottom ends of the rightand left fixed masts. Therefore, by use of the right and left fixedmasts, the supporting leg body can be supported in a vicinity of atravel road surface. That is to say, a structure to prevent turnover ofa traveling body can be simply configured with the supporting leg bodyand the locking mechanism.

According to the invention according to claim 6, the locking mechanismis configured to lock the supporting leg body by further upward movementof the grass collector after the supporting leg body approaches in alanding direction by upward movement of the grass collector. Therefore,while the supporting leg body changes from a retracting posture, apartfrom a landing surface, to a landing position, the supporting leg bodycan be prevented from being locked by the locking mechanism.Accordingly, the supporting leg body is certainly locked in the landingposture by the locking mechanism, and the grass collector can be liftedup. Also, the supporting leg body is configured to get away from thelanding surface by further downward movement of the grass collectorafter the locking mechanism gets away from the supporting leg body bydownward movement of the grass collector. Therefore, until unlocking thesupporting leg body in the landing posture, the supporting leg bodycannot be retracted to get away from the landing surface by downwardoperation of the grass collector. Accordingly, the supporting leg bodyretracted by downward operation of the grass collector can be preventedfrom being damaged. Also, an operator can be prevented from forgettingunlocking the grass collector, and a mowing operation for the lawngrass, etc. can be resumed after the supporting leg body is certainlyreturned to the retracting posture where the supporting leg body is awayfrom the landing surface.

According to the invention according to claim 7, a lawn mower comprisesa grass collector supported to the traveling body through the lift drivemeans to be lifted up and down and rotatably supported to the travelingbody through dump drive means, a braking operation body for operating tobrake a traveling part of the traveling body, a lifting operation bodyfor operating the lift drive means, and a rolling operation body foroperating the dump drive means, wherein permission control means fordetecting a braking operation of the braking operation body andpermitting each operation of the lifting operation body and the rollingoperation body is provided. Therefore, in a state that an operatorforcibly brakes the traveling part, lift drive means or dump drive meanseach can be operated, misoperation of the lifting operation body or therolling operation body can be reduced, and the mowed grass in the grasscollector can be simply prevented from being discharged at unexpectedplaces.

According to the invention according to claim 8, a lawn mower comprisescheck control means in which one operation of the lifting operation bodyand rolling operation body restricts the other operation thereof.Therefore, in a state that an operator forcibly brakes the travelingpart, a lifting operation of the grass collector or rolling operation ofthe grass collector can be selectively performed. That is to say, in astate that the traveling body is certainly stopped, according to aninitial procedure, an operation of discharging the mowed grass in thegrass collector is performed, and overturn of the lawn mower can beeasily prevented. Accordingly, the lawn mower with a lighter weight canprovide reduction in manufacturing costs, and increase in volume of thegrass collector can improve operability in mowing the grass, etc.

According to the invention according to claim 9, a lawn mower comprisesan engine stop mechanism for stopping an engine mounted on the travelingbody, a PTO operation body for operating to drive or stop the mowerdevice, PTO detection means for detecting an operation of the PTOoperation body in order to drive the mower device, and parking brakedetecting means for detecting an operation of parking brake to be on inorder to keep the traveling parts of the traveling body in a brakedstate, wherein the engine stop mechanism is configured to operate by adriving operation of the mower device during an operation of the parkingbrake to be on. Therefore, the engine can be stopped by misoperation ofthe PTO operation body, improper driving of the mower device due tomisoperation by an operator can be easily prevented, and drivability oroperability of mowing operation for the operator can be improved.

According to the invention according to claim 10, a lawn mower comprisesa hydraulic lift cylinder, as the lift drive means, having a piston rodthat advances upward, wherein the lift cylinder is disposed between theright and left fixed masts, both ends of mast traction bodies areconnected to the traveling body and movable masts, the masts tractionbodies are stretched through tip guide pulleys disposed at a tip end ofthe piston rod, both ends of lift traction bodies are connected to thetraveling body and a lift frame body, the lift traction bodies arestretched through movable guide pulleys disposed at top ends of themovable masts. Therefore, the lift frame body can be lifted up toward anupper end of the movable mast projecting from an upper end of the fixedmast, and when the mowed grass is discharged, the grass collector can belifted up to a extremely high position. On the other hand, the movablemast and the lift frame body can be lifted down within a height range ofthe fixed mast, and during the mowing operation in a state that thegrass collector is lowered, the overall body height can be lowered.Also, a hydraulic pressure structure of the lift mechanism for liftingup and down the grass collector can be simply configured owing toprovision of a single hydraulic lift cylinder.

According to the invention according to claim 11, the grass collectorcomprises a grass collection main body disposed in the lift mechanism,and a cover openably and closably disposed on a rear face side of thegrass collector, wherein a bottom rear end of the grass collector isconnected to a rear end of the lift frame body projecting backward fromthe movable masts by a dump fulcrum shaft, the grass collection mainbody is configured to rotate backward around the dump fulcrum shaft, andat the same time, a top front end of the cover is connected to a toprear end of the grass collector through a pin-structured opening/closingfulcrum shaft capable of being attached and removed by one-touchoperation, the cover is configured to rotate backward and upward aroundthe opening/closing fulcrum shaft, and the cover is configured capableof being separated from the grass collection main body by removal of thefulcrum shaft from the grass collection main body connected to thecover. Therefore, only by removing the opening/closing fulcrum shaftfrom the grass collection main body, without any tools, the cover can besimply separated from the grass collection main body. For example, thegrass collection main body separated from the cover can be simply usedfor a dust collection operation, etc. for discharging branches of treesand duct, etc into containers.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an overall side view showing a lawn mower;

FIG. 2 is a plan view of FIG. 1;

FIG. 3 is a side view showing a rear part of a traveling body and agrass collector;

FIG. 4 is a rear view showing a lift mechanism;

FIG. 5 is an enlarged view partially showing the lift mechanism of FIG.4;

FIG. 6 is a side view showing a discharging state of mowed grass fromthe grass collector;

FIG. 7 is a hydraulic circuit diagram;

FIG. 8 is a side view showing a fixed portion of a lift lever and a dumplever;

FIG. 9 is a plan view showing the fixed portion of the lift lever andthe dump lever;

FIG. 10 is a drawing explaining an operation of a dump lever;

FIG. 11 is a drawing explaining an operation of a lift lever;

FIG. 12 is a side view showing a fixed portion of a supporting leg body;

FIG. 13 is a side view showing a state that the supporting leg body islanded.

FIG. 14 is a side view showing a state that the supporting leg is lockedin a landing position;

FIG. 15 is an enlarged view partially explaining a grass collection box;

FIG. 16 is an overall side view showing another embodiment;

FIG. 17 is a diagram of a circuit used to stop an engine;

FIG. 18 is a functional block diagram of control means of a grasscollection operation;

FIG. 19 is a flowchart of control of a grass collection operation;

FIG. 20 is a control circuit diagram showing another embodiment of FIG.17.

BRIEF DESCRIPTION OF NUMERALS

-   -   1 traveling body    -   6 rear wheel (traveling part)    -   9 engine    -   13 brake pedal (braking operation body)    -   16 mower device    -   18 PTO clutch lever (PTO operation body)    -   29 discharge duct    -   30 grass collection box (grass collector)    -   31 lift mechanism    -   axle frame    -   45 fixed mast    -   46 movable mast    -   47 lift frame body    -   48 lift cylinder (lift drive means) (first double speed        mechanism)    -   50 base flame    -   55 piston rod    -   58 lift wire (mast traction body)    -   59 lift wire (mast traction body)    -   66 triple pulley (tip guide pulley) (first double speed        mechanism)    -   72 dump fulcrum shaft    -   74 lift-up wire (lift traction body) (second double speed        mechanism)    -   75 lift-up pulley (movable guide pulley) (second double speed        mechanism)    -   76 grass collection main body    -   77 cover    -   78 dump cylinder (damp drive means)    -   83 opening/closing fulcrum shaft    -   89 mowed grass    -   110 lift lever (lifting operation body)    -   111 dump lever (rolling operation body)    -   120 locking arm body (permission control means)    -   121 check arm body (check control means)    -   132 supporting leg body    -   137 outrigger locking mechanism    -   150 PTO clutch engagement sensor (PTO detection means)    -   151 engine stop solenoid (engine stop mechanism)    -   153 parking lever (parking brake)    -   154 parking brake sensor (parking brake detecting means)

Preferred embodiments of the present invention are described below withreference to the accompanying drawings. FIG. 1 is a side view showing alawn mower, FIG. 2 is a plan view of the lawn mower, FIG. 3 is a sideview showing the rear of a traveling body and a grass collector, FIG. 4is a rear view showing a lift mechanism, FIG. 5 is an partially enlargedview showing the lift mechanism of FIG. 4, FIG. 6 is a side view showinga discharging state of mowed grass from the grass collector, and FIG. 7is a hydraulic circuit diagram. As shown in FIG. 1 and FIG. 2, in thelawn mower of the embodiment, a traveling body 1 includes right and leftbody frames 3,4 connected integrally with each other through a pluralityof lateral frames (not shown). The body frames 3,4 are supported byright and left front wheels 5 and right and left rear wheels 6, whichare disposed in the front and rear of both right and left sides of thebody frame.

The front upper surface of the traveling body 1 is covered with a frontcover 7. An engine 9 as a power source is covered by a hood 8 located onthe front cover 7. A steering column 11 with a round shaped steeringwheel 10 is mounted on the rear of the hood 8. A speed change pedal 12for adjusting the speed of the vehicle (running speed of the travelingbody 1) and a brake pedal 13 for braking the traveling body 1 (rearwheels 6) are disposed on the front cover 7 (on a step) in the right ofthe steering column part 11 in the driving direction.

The rear upper surface of the traveling body 1 is covered with a rearcover 14. A driver seat 15 is provided on the rear cover 14. When anoperator on the driver seat 15 rotates the steering wheel 10 and ahydraulic torque generator 2 for power steering is operated according tothe rotating amount (rotation angle) of the steering wheel 10, thesteering angle (operating angle) of the right and left front wheels 5 isvaried. At the left of the driver seat 15, a mower lift lever 17 isprovided for forward and backward rotation. A mower device 16 for mowinglawn grass described below is lifted up and down by the mower lift lever17. At the right of the driver seat 15, a PTO clutch lever 18 isprovided for forward and backward rotation. The mower device 16 isstarted and stopped by the PTO clutch lever 18.

A transmission case 19 is disposed in the rear cover 14. Thetransmission case 19 includes a continuously variable, hydrostatictransmission 95 (HST type) described below. The transmission case 19 isdisposed in the rear part of the body frames 3,4 (the part inclineddownwardly from back to front). The transmission case 19 is configuredto transfer power from the engine 9 to the right and left rear wheels 6after changing the speed. A fuel tank 20 is mounted on the rear ends ofthe body frames 3,4. Fuel is supplied from the fuel tank 20 to theengine 9. An oil tank 21 is mounted outside the inclined portion of theright body frame 4. Hydraulic fluid will be supplied from the oil tank21 to the continuously variable, hydrostatic transmission 95 etc. in thetransmission case 19. A battery 22 for the engine 9 is mounted outsidethe inclined portion of the left body frame 3. The fuel tank 20 isdisposed between the oil tank 21 and the battery 22.

On the bottom end of body frame 3,4, the mower device 16 is mounted forlifting up and down through link mallets 23, 24. The mower device 16 isdisposed between the right and left front wheels 5 and the right andleft rear wheels 6. The mower device 16 includes a bowl-shaped mowercase 25 opening downward, and a right and left pair of rotary mowingblades 26 enabling horizontal rotation. The rotary mowing blades 26 aredisposed in the mower case 25. Also, four gauge wheels 27 are attachedto front and back of the right and left sides in the front and back ofthe mower case 25. A height of the mower device 16 to the ground duringmowing (i.e., lowered position of the mower device 16) will be regulatedby the gauge wheels 27. A duct part 28 is provided on the top of themower case 25. The duct part 28 opens backward.

The duct part 28 is communicated with a front side of the discharge duct29. The discharge duct 29 is disposed between right and left rear wheels6 in the bottom side of the body frame 3,4. Also, a grass collection box30 as a grass collector is communicated with the rear side of thedischarge duct 29. The grass collection box 30 is made of mesh sheetformed in a cubic shape. The grass collection box 30 is liftablysupported on the rear side of the traveling body 1 (through the liftmechanism 31). When grass such as lawn grass is mowed by the rotarymowing blades 26 in the mower case 25, the mowed grass is transported tothe grass collection box 30 through the discharge duct 29 from the ductpart 28 by the wind generated by the rotary mowing blade 26. The grassmowed by the mower device 16 is collected in the grass collection box30. The lift mechanism 31 is disposed in the rear part of the travelingbody 1.

Next, referring to FIG. 1 and FIG. 2, a powertrain system of the lawnmower will be described below. In the lawn mower of the embodiment, atwo-wheel drive system, in which part of rotational power of the engine9 is distributed into both the right and left rear wheels 6, is adopted.That is to say, the lawn mower includes an output shaft 32longitudinally projecting from the engine 9, a propeller shaft 33 withthe universal joint at both the front and rear ends, and a transmissionrelay case for traveling 34 disposed more forwardly than thetransmission case 19. The part of the rotary power of the engine 9 willbe transmitted from the rear end of the output shaft 32 to thetransmission case 19 through the propeller shaft 33, the transmissionrelay case for traveling 34, and an endless input belt 35. The rotarypower converted by the transmission case 19 is transmitted from theright and left rear wheel drive shafts 36 to right and left axles 38through right and left endless rear wheel drive chains 37. As a result,the right and left rear wheels 6 fixed to the right and left axles 38 isrotationally driven. From the transmission case 19, horizontal right andleft rear wheel drive shafts 36 are projected laterally. The right andleft axle 38 is provided in the backside part of the traveling body 1.Right and left axle frames 39 are provided in the backside part of theright and left body frame 3,4 respectively, the right and left axles 38are disposed in the right and left axle flames 39. The discharge duct 29described above is extended between the right and left axle flames 39 inthe front back direction.

As shown in FIG. 1, the discharge duct 29 for transporting mowed grass(mowed lawn grass) is extended between the mower device 16 (mowing grasspart) in the bottom side of the traveling body 1 and the grasscollection box 30 in the backside of the traveling body 1. Thetransmission case 19 is supported on the part of the traveling body 1inclined downwardly from back to front above the discharge duct 29 insuch a way that the transmission case 19 is inclined downwardly fromback to front. The lift mechanism 31 is disposed in the traveling body 1more backwardly than the transmission case 19 through an axle frame 39.Accordingly, a cross-section area (dimensions of height and width) forventilation of the discharge duct 29 can be formed in a predeterminedsize so that the clog of mowed grass in the discharge duct 29 can beprevented. In addition, by using a simple assembly structure, the liftmechanism 31 can be supported to the traveling body 1 through the axleframe 39 with high rigidity.

On the other hand, the other rotary power of the engine 9 is transmittedfrom the front end of output shaft 32 to a PTO shaft 42 through anendless PTO transmission belt 41 for PTO power transmission. The PTOshaft 42 is supported in the front part of the body frame 4.Subsequently, the power is transmitted from the PTO shaft 42 to agearbox 44 for a mower through countershaft 43 with universal joints atboth the front and back ends. As a result, a left rotary mowing blade 26in the mower case 25 is driven clockwise in a plan view. A right rotarymowing blade 26 is driven counter clockwise in a plan view. While mowinglawn grass etc. is mowed with the right and left rotary mowing blades26, the mowed grass is collected in the center of the right and leftwidth of the mower case 25 and is discharged from the duct part 28 tothe discharge duct 29. The gearbox 44 for a mower is disposed on themower case 25 in a more rightwardly than the body frame 4.

In the configuration described above, the power of the engine 9 istransmitted to the transmission case 19 with a single propeller shaft33. Also, while maintaining the cross-section area (dimensions of heightand width) for ventilation of the discharge duct 29 in a predeterminedsize and placing the transmission case 19 in the higher portion of thetraveling body 1, the propeller shaft 33 can be lowered by the verticaltransmission dimension of the transmission relay case 34. Accordingly,even if the propeller shaft 33 is disposed below the step (front cover7) between the engine 9 and the transmission case 19, a step for theoperator on the driver seat 15 to put his/her feet can be formed in alower position. That is to say, there is an advantage that thefollowings are achieved simultaneously: simple configuration of thepowertrain mechanism to the transmission case 19, smooth discharge ofmowed grass with an arrangement of a large discharge duct 29 in thecenter of the right and left width of the traveling body 1, and simplegetting on and off of the operator to the driver seat 15.

Next, referring to FIGS. 3 to 5, the structure of the lift mechanism 31is described below. As shown in FIG. 3 and FIG. 4, the lift mechanism 31comprises parallel right and left fixed masts 45 erected at the rear ofthe traveling body 1, parallel right and left movable masts 46 supportedto be lifted up and down to the right and left fixed masts 45, liftframe bodies 47 supported to be lifted up and down to the right and leftmovable masts 46 and a single hydraulic lift cylinder 48 lifting up anddown the movable masts 46 and the lift frame bodies 47.

As shown in FIGS. 3 to 5, mast supporting bodies 45 a with a square pipeshape are provided in front of the right and left fixed masts 45. Byinserting the mast supporting bodies 45 a into inner holes of body frame3,4 with a square pipe shape from the rear end, the right and left fixedmasts 45 are supported by the right and left body frame 3,4. Also, thebottom ends of the right and left fixed masts 45 are fastened to therear ends of the right and left axle frames 39 with bolts 49. Themounting width between the right and left fixed masts 45 is larger thanthe right and left width of the discharge duct 29 and is smaller thanthe distance between the insides of the right and left rear wheels 6.That is to say, in a back view, the right and left fixed masts 45 arerespectively disposed between the right and left outside surface of thedischarge duct 29 and the right and left rear wheels 6 (see FIG. 4).

Both the ends of the base frame 50, which is in a shape of ahorizontally long pipe, are welded to the center of the right and leftfixed masts 45 in the vertical direction. The bottom end of the liftcylinder 48 is connected to the center part of the base frame 50 througha receive bolt 51. The base frame 50 is disposed at a higher positionthan the top of the discharge duct 29. An auxiliary duct 52 is fixed tothe bottom of the base frame 50. Accordingly, during a mowing operation,the gap formed between the discharge duct 29 and the grass collectionbox 30 is blocked by the auxiliary duct 52. The auxiliary duct 52prevents the mowed grass from getting out between the discharge duct 29and the grass collection box 30. To the bottom of the grass collectionbox 30, a cutout (not shown) that the auxiliary duct 52 can verticallypass through is formed. Accordingly, even if the grass collection box 30moves vertically (moves up or moves down), the bottom of the grasscollection box 30 does not contact with the auxiliary duct 52.

As shown in FIG. 5, both the ends of the horizontally long support frame53 and a bearing receive plates 54 are integrally weld to the top endsof the right and left fixed masts 45. The middle part of the liftcylinder 48 is fixed to the support frame 53 through a U-shaped bolt 53a. The lift cylinder 48 is erected and approximately parallel to thefixed masts 45 at the center position between the right and left fixedmasts 45. A piston rod 55 is extended upwardly from the top end of thelift cylinder 48.

As shown in FIGS. 3 to 5, the right and left movable masts 46 aredisposed to be vertically slidable on the outside of the right and leftfixed masts 45 through a plurality of guide rollers 56. The right andleft movable masts 46 are connected to be vertically slidable throughhorizontal frames 57. The support frame 53 and the right and leftmovable masts 46 are interconnected by lift wires 58, 59 describedbelow.

Both the ends of the left lift wire 58 are connected to the bottom endof the movable mast 46 on the left in the forward direction of thetraveling body 1 through the wire fixture 60. A folding back pulley 63is provided to the support frame 53 through a tension adjustment bolt 61and a bearing body 62. The middle part of the left lift wire 58 is woundaround the folding back pulley 63. Double pulleys 64 a, 64 b areprovided to the top end of the left fixed mast 45 through the bearingreceive plate body 54. A triple pulley 66 is provided to the top end ofthe piston rod 55 through a spindle 65. And, the left lift wire 58 shownwith two-dot chain line in FIG. 5 is provided in a double stretchedstate between the wire fixture 60 and the folding back pulley 63,through the double pulleys 64 a,64 b and the pulleys 66 a, 66 b disposedon both sides of the triple pulley 66.

On the other hand, the end of the right lift wire 59 is connected to thebottom end of the movable mast 46 on the right side facing in theforward direction of the traveling body 1 through the wire fixture 67. Atension adjustment bolt 68 is provided on the support frame 53. Theother end of the right lift wire 59 is connected to the tensionadjustment bolt 68. A pulley 69 of the fixed mast side is provided atthe top end of the right fixed mast 45 through the bearing receive plate54. The right lift wire 59 shown with dashed line in FIG. 5 is providedin a single stretched state between a wire fixture 67 and the tensionadjustment bolt 68 through the pulley 69 of the fixed mast side and thecenter pulley 66 c of the triple pulley 66.

In the above configuration, when the piston rod 55 is advanced upwardly,and the triple pulley 66 is lifted up, the ascending stroke of the rightand left masts 46 is twice as much as the advancing stroke of the pistonrod 55. In addition, the left lift wire 58 is stretched double and theright lift wire 59 is stretched single, and thus even if the rotationalforce is generated around an axis line of the piston rod 55, the liftwire 58 opposes the rotational force and prevents rotation of the pistonrod 55 about the axis line. Accordingly, the twists of the wires 58, 59at the pulley 66 can be prevented. When the left lift wire 58 and theright lift wire 59 are configured with a wire with the same diameter,the supporting force of the left movable mast 46 (double lift wire 59)becomes larger than that of the right movable mast 46 (single lift wire59) in the traveling direction of the traveling body 1.

As shown in FIGS. 3 to 5, the lift frame bodies 47 are disposed to bevertically slidable on the outside of the right and left movable masts46 through a plurality of guide rollers 70. The lift frame bodies 47comprise right and left fork bodies 71 extending approximatelyhorizontally in the front and back direction and dump fulcrum shafts 72supporting the above described grass collection box 30 rotatably. Thelift frame bodies 47 are supported to the right and left movable masts46. The front end of the right and left fork bodies 71 are connected tothe lift frame bodies 47. The dump fulcrum shafts 72 are disposed in therear end of the right and left fork bodies 71. Thus, the grasscollection box 30 rotates around the dump fulcrum shafts 72 to thebackward of the traveling body 1.

Tension adjustment bolts 73 are provided outside the right and left ofthe lift frame bodies 47. Both the ends of right and left lift-up wires74 are connected to the tension adjustment bolts 73 and the right andleft bearing receive plate bodies 54. Lift-up pulleys 75 are provided tothe top end of the right and left movable masts 46 respectively. Theright and left lift-up wires 74 shown with dashed lines in FIG. 5 areprovided in a stretched state through the lift-up pulleys 75. That is tosay, the ascending stroke of the lift frame body 47 is twice as much asthat of the movable mast 46.

Accordingly, the ascending stroke of the lift frame body 47 is fourtimes as much as the advancing stroke of the piston rod 55. As a result,the elevating length of the grass collector 30 can be made to large byuse of an inexpensive lift cylinder 48 having a piston rod 55 of shortadvancing/retracting stroke. In the rear of the traveling body 1, thegrass collection box 30 can be lifted up by the maximum lift height Hfrom a grass collection position to a grass discharging position (seeFIG. 4).

Next, referring to FIG. 3 and FIG. 6, the structure of the grasscollection box 30 is described. As shown in FIG. 3 and FIG. 6, the grasscollection box 30 includes a grass collection main body 76 communicatingwith the discharge duct 29 and a cover 77 shutting an opening in therear face of the grass collection main body 76 openably and closably.The grass collection box 30 in a square box shape is formed in such away that the cover 77 shaped triangle in a side view is devised with thegrass collection main body 76 shaped trapezoid in a side view.

The rear end of the bottom of the grass collection main body 76 (thebottom end of the rear opening side of the grass collection main body76) is connected to the dump fulcrum shaft 72. A dump cylinder 78 isdisposed outside the fork body 71 on the left side in the travelingdirection of the traveling body 1. The dump cylinder 78 is connected tothe left fork body 71 through a cylinder connection shaft 78 a. A dumparm 79 is provided on the left side end of the dump fulcrum shaft 72.The dump arm 79 is connected to the top end of the piston rod 80 of thedump cylinder 78 with a shaft 81. Accordingly, by advancing the pistonrod 80, the grass collection main body 76 rotates backward about thedump fulcrum shaft 72. That is to say, the flat bottom of the grasscollection main body 76 is inclined with its affront high and rear low.The rear end of the grass collection main body 76 opens obliquelydownward to the rear (see FIG. 6).

An opening/closing fulcrum shaft 83 is disposed at the rear end of thetop face frame 82 of the grass collection main body 76 (the top end ofthe rear opening of the grass collection main body 76). The front end ofthe top face of the cover 77 is connected to the opening/closing fulcrumshaft 83. The cover 77 rotates about the opening/closing fulcrum shaft83 and moves from an open position to a closed position. The right andleft ends of the opening/closing fulcrum shaft 83 are projected in boththe right and left direction of grass collection main body 76. One endsof paired right and left opening/closing operation arms 84 arerespectively connected to the right and left ends of the opening/closingfulcrum shaft 83. Ends of an opening/closing operation link 87 areconnected to the fork body 71, which is in the front side of the dumpfulcrum shaft 72, and to the other end of the opening/closing operationarm 84, which is extended forward from the opening/closing fulcrum shaft83, through shafts 85, 86 respectively. An opening/closing linkmechanism 88 is formed by the right and left pair of opening/closingoperation arms 84 and the right and left pair of the opening/closingoperation links 87. The opening/closing link mechanism 88 works with therotation of the grass collection main body 76 about the dump fulcrumshaft 72 (see FIG. 6).

That is to say, when the grass collection main body 76 rotates backwardabout the dump fulcrum shaft 72 and moves to a discharge position of themowed grass, the opening/closing fulcrum shaft 83 rotates backward aboutthe dump fulcrum shaft 72. Also, the opening/closing fulcrum shaft 83moves in a direction away from the shaft 85. The opening/closingoperation arm 84 is pulled by the opening/closing operation link 87 of aconstant length. That is to say, the cover 77 rotates backward about theopening/closing fulcrum 83 by the opening/closing link mechanism 88, andmoves to the opening position (a position illustrated in a solid line inFIG. 6). The grass collection main body 76 and the cover 77 areconnected through the opening/closing fulcrum shaft 83 in an inversed-Vshape. The rear opening of the grass collection main body 76 is openedobliquely downward to the rear. The front opening of the cover 77 isopened obliquely downward to the front. Accordingly, the mowed grass 89in the grass collection main body 76 and the cover 77 are dropped intothe approximately center of the top opening of the lower container 90(see FIG. 6).

On the other hand, with retraction of the piston rod 80 caused by theoperation of the dump cylinder 78, the grass collection main body 76rotates forward about the dump fulcrum shaft 72 and returns to theposition for collecting mowed grass. In the case, in association withthe rotation of the grass collection main body 76 about the dump fulcrumshaft 72, the cover 77 is rotated forward about the opening/closingfulcrum shaft 83 by the opening/closing link mechanism 88 and returns tothe closed position (a position illustrated in a solid line in FIG. 3)

Next, referring to FIG. 7, a hydraulic circuit 91 of the lawn mower ofthe present embodiment is described. As shown in FIG. 7, the hydrauliccircuit 91 comprises a hydraulic charge pump 92 actuated by rotationalforce of the engine 9, a hydraulic shift pump 93 of a variable capacitytype, and a hydraulic shift motor 94 of a constant capacity typeoperated by high-pressure fluid oil discharged from the hydraulic shiftpump 93. A continuously variable, hydrostatic transmission 95 iscomprised of the hydraulic shift pump 93 and the hydraulic shift motor94. The continuously variable, hydrostatic transmission 95 is built inthe transmission case 19 described above. The rotational power of theengine 9 is shifted by the continuously variable, hydrostatictransmission 95, and the shifted output is transmitted to the right andleft rear wheels 6.

As shown in FIG. 7, the suction side and the discharge side of thehydraulic shift pump 93 and those of the hydraulic shift motor 94 areconnected to each other through a closed loop hydraulic circuit 96. Thehydraulic shift pump 93 is driven by the power of the engine 9. When, anangle of a cam plate 97 of the hydraulic shift pump 93 is adjusted byoperating the gear shift pedal 12, a rotational output of the hydraulicshift motor 94 is changed. The number of revolutions of the axle 38driven through the hydraulic shift motor 94 is varied. Thus, therotational speed of the rear wheels 6 driven through the axle 38 isvaried.

As shown in FIG. 7, the hydraulic circuit described above comprisesrelief valves, oil filters, check valves, etc. A strainer 99 in the oiltank 21 (a hydraulic fluid tank) is connected to the suction side of thehydraulic charge pump 92 through a low-pressure charge oil passage 98. Ahigh-pressure charge oil passage 102 is connected to the discharge sideof the hydraulic charge pump 92. A relief valve 100 for supplying and arelief valve 101 for returning are disposed in the high-pressure chargeoil passage 102. The high-pressure charge oil passage 102 is connectedto a closed loop oil circuit 96 through the relief valve 100 forsupplying, a check valve 103 for forward travel supplying, and the checkvalve 104 for reverse travel supplying.

Accordingly, hydraulic fluid from the hydraulic charge pump 92 is alwayssupplied to the closed loop oil passage 96 during the operation of theengine 9. Also, if there is surplus hydraulic fluid in the charge oilpassage 98, 102 that supply hydraulic fluid from the hydraulic chargepump 92 to the closed loop oil passage 96, the surplus hydraulic fluidin the charge oil passages 98, 102 is returned to the oil tank 21through the relief valve 101 for returning.

On the other hand, a bypass valve 105 is connected to the closed loopoil passage 96. The suction side and discharge side of the hydraulicshift pump 93 and those of the hydraulic shift motor 94 areshort-circuited by the bypass valve 105. When the bypass valve 105 isswitched, as shown in FIG. 7, by the operation of a bypass switch lever106 and the suction side and the discharge side of the hydraulic shiftpump 93 and those of the hydraulic shift motor 94 are off (the state ofthe bypass valve 105 shown in FIG. 7), the hydraulic shift pump 93 andthe hydraulic shift motor 94 are connected in a traveling drive state,and the rear wheels 6 are driven by the rotational power of the engine9.

On the other hand, when the bypass valve 105 is switched by theoperation of the bypass switch lever 106, and thus the suction side andthe discharge side of the hydraulic shift pump 93 and those of thehydraulic shift motor 94 are short-circuited, the hydraulic shift motor94 can be held in a freely rotating state (a freely rotating state undera no-load condition). For example, if there is a failure that fuel inthe fuel tank 20 disappears, and the rear wheels cannot be driven by thepower of the engine 9, the operator can operate the bypass switchinglever 106 to switch the bypass valve 105, and can push the travelingbody 1 to move with keeping the stepless speed device 95 of thetransmission case 19 in a no-load condition.

As shown in FIG. 7, a hydraulic lift valve 107 for lifting is providedfor supplying to hydraulic fluid a lift cylinder 48 of a double-actingtype for lifting the grass collection box 30. The hydraulic charge pump92 is connected to the hydraulic lift valve 107 for lifting through acheck valve 108 for preventing malfunction. A dump valve 109 is providedfor discharging the mowed grass 89 in the grass collection box 30. Thedump valve 109 is connected to a tank port of the lift valve 107.Accordingly, when the operator operates a lift lever 110 to switch thelift valve 10 and operates the lift cylinder 48, the grass collectionbox 30 in a position for collecting grass starts rising. When theoperator operates a dump lever 111 to switch the dump valve 109 andoperates the dump cylinder 78, as shown in FIG. 6, the grass collectionbox 30 starts dumping operation, and the mowed grass in the grasscollection box 30 is discharged into the container 90.

When the mowed grass in the grass collection box 30 is completelydischarged, the operator operates the dump lever 111 to return the grasscollection box 30 to a supporting position of the lift frame body 47.Then, the operator operates the lift lever 110, putting the grasscollection box 30 back in the position for collecting grass in the rearpart of the traveling body 1. The operation for mowing grass, etc isrestarted.

The torque generator 2 for power steering is connected to the tank portof the tank valve 109. The torque generator 2 is also connected to thereturning relief valve 101 through a line filter 112 and a relief valve113. The torque generator 2 is composed of a control valve (not shown)switched by the operation of the steering wheel 10, a hydraulic pumpoperated through the control valve, and the like. The torque generator 2generates large hydraulic power by the operation of the steering wheel10. The front wheels 5 are changed in direction (steered) by largehydraulic power of the torque generator 2 (a hydraulic pump). Thehydraulic fluid from the torque generator 2 is returned to the oil tank21 through the line filter 112.

The lift valve 107, the dump valve 109, and the torque generator 2 areconnected in series with respect to the hydraulic charge pump 92. Duringthe operation of a lift cylinder 48 after switching the lift valve 107,neither the dump cylinder 78 nor the torque generator 2 is operated.During the operation of the dump cylinder 78 after switching the dumpvalve 109, torque generator 2 not operated. When neither the liftcylinder 48 nor the dump cylinder 78 is operated, the torque generator 2is operated. That is to say, the lift cylinder 48 is operatedpreferentially to the dump cylinder 78 and the torque generator 2. Also,the dump cylinder 78 is operated preferentially to the torque generator2. Therefore, the hydraulic charge pump 92 can be formed by using aninexpensive hydraulic pump with a small capacity (small output), andthus, manufacturing cost of the hydraulic system can be reduced.

Next, referring to FIGS. 8 to 11, a mounting structure of the lift lever110 and the dump lever 111 is described. As shown in FIG. 8 and FIG. 9,a hydraulic piping block 114 and a hydraulic valve device body 115 areprovided inside a hydraulic device case 116. The hydraulic piping block114 connects hydraulic piping (not shown) to the hydraulic charge pump92, the lift cylinder 48, and the dump cylinder 78. The hydraulic valvedevice body 115 includes the lift valve 107 and the dump valve 109.

The bottom end of the hydraulic valve device body 115 is integrallyfixed to the top end of the hydraulic piping block 114. Also, on topside of the rear part of the rear cover 14, the hydraulic device case116 is disposed through the right body frame 4 (see FIG. 1). Thehydraulic device case 116 is disposed obliquely backward from the rightside of the driver seat 15 (see FIG. 2).

As shown in FIGS. 8 to 11, the lift lever 110 and the dump lever 111 aredisposed to be vertically movable through a lever bearing part 117 onthe front face of the hydraulic valve device body 115. When the liftvalve 107 is in a neutral position, the lift lever 110 is projected tothe hydraulic valve device body 115 approximately horizontally. When theoperator holds the lift lever 110 and rotates it upwardly or downwardlyabout a fulcrum of the lever bearing part 117, the lift valve 107 isswitched to an ascending side or a descending side, and the liftcylinder 48 is operated in the ascending side or descending side. Whenthe dump valve 109 is in a neutral position, the dump lever 111 isprojected to the hydraulic valve device body 115. When the operatorholds the lift lever 111 and rotates it upwardly or downwardly about thefulcrum of the lever bearing part 117, the dump valve 109 is switched tothe opening side or closing side, and the dump cylinder 78 is operatedin the opening side or closing side.

As shown in FIG. 8 and FIG. 9, a locking arm body 120 and a restrainingarm body 121 are supported via a spindle 112 by a lever guide body 118provided in side the hydraulic device case 116. The lift lever 110 andthe dump lever 111 are rotatably guided upwardly or downwardly by thelever guide body 118. The locking arm body 120 is connected to the brakepedal 13 through the braking detection wire 119. By switching operationof either the lift lever 110 or the dump lever 111, switching operationof the other thereof is restricted by the restricting arm body 121.

As shown in FIG. 9, a mowed grass discharge control notch 120 a isformed in the locking arm body 120. The middle part of the lift lever110 is engaged with in the mowed grass discharge control notch 120 a. Alift checking notch 121 a and a dump checking notch 121 b are formed inthe check arm body 121. The middle part of the lift lever 110 is engagedwith the lift checking notch 121 a. The middle part of the dump lever111 is engaged with the dump checking notch 121 b. A pair of pressurerollers 123, 124 is supported by the check arm body 121 through rollershafts 125, 126. The pair of pressure rollers 123,124 is contacted withthe middle part of the lift lever 110. The pair of pressure rollers 123,124 are disposed so as to interpose the lift checking notch 121 atherebetween.

As shown in FIG. 9, a braking detection spring 127 in a shape of a clipspring and a release spring 128 in a shape of a tension spring areprovided. One end 127 a of the braking detection spring 127 is hooked tothe locking arm body 120. The other end 127 b of the braking detectionspring 127 is hooked to a connecting pin 129 described below. Thebraking detection spring 127 rotates the locking arm body 120 in adirection that the mowed grass discharge notch 120 a is separated fromthe lift lever 110. Both ends of the release spring 128 are hooked to aroller shaft 125 and the connecting pin 129 respectively. The releasespring 128 rotates the checking arm body 121 in a direction that thedump checking notch 121 b is separated from the dump lever 111.

As shown in FIG. 8 and FIG. 9, the middle part of the locking arm body120 is fitted to the spindle 122. A fitting part 130 attached to the oneend of the braking detecting wire 119 is engaged with one end of thelocking arm body 120 through the connecting pin 129. Also, a stopperbody 131 is integrally formed with the other end of the locking arm body120. The stopper body 131 supports the locking arm body 120 in aposition where the mowed grass discharge notch 120 a is separated fromthe lift lever 110.

The spring force of the braking detection spring 127 is arranged to besmaller than that of the pedal returning spring which is not shown infigures and holds the brake pedal 13 at an initial position (a brakereleasing position). The spring force of the release spring 128 isarranged to be smaller than that of the braking detection spring 127.

In the configuration described above, as shown in FIG. 9, when the brakepedal 13 is held in the initial position (a brake releasing position) bythe pedal returning spring, which is not shown, the braking detectingwire 119 is pulled by the spring force of the pedal returning spring.Therefore, the locking arm body 120 is held in an approximately constantposition while opposing the spring force of the braking detection spring127. That is to say, a state that the lift lever 110 is engaged with themowed grass discharge notch 120 a is maintained. On the other hand, aside edge 120 b of the locking arm body 120 and the pressure roller 124contact with each other by the spring force of the release spring 128.Therefore, the check arm body 121 is held in an approximately constantposition. That is to say, a state that the dump lever 111 is locked inthe dump checking notch 121 b is maintained.

Accordingly, while the brake pedal 13 is not depressed by the operatorand thus is not both the operation of the lift lever 110 and that of thedump lever 111 are restricted by the locking arm body 120 and therestricting arm body 121. In the case of mowing grass etc., the operatorseparates the right foot from the brake pedal 13 and depresses the shiftpedal 12 with the right foot. Subsequently, the traveling body 1 moves,the mowing operation is performed, and the grass mowed by the mowerdevice 16 is collected to the grass collection box 30.

On the other hand, as shown in FIG. 10, when the rear wheels 6 arebraked by the operation of the brake pedal 13 by the operator, thebraking detecting wire 119 is loosened. Thus, by spring force of thebraking detection spring 127, the position of the locking arm body 120is held and the lift lever 110 is held to be away from the mowed grassdischarge notch 120 a. In the case, the stopper 131 contacts the top ofthe lever guide body 118. Also, the lift lever 110 and the pressurerollers 123,124 are in contact with each other by the spring force ofthe release spring 128. Therefore, the check arm body 121 is held in theposition, and a state that the dump lever 111 is away from the dumpchecking notch 121 b is maintained.

That is to say, in the state of FIG. 10 where the dump checking notch121 b is away from the dump lever 111, the lift lever 110 or the dumplever 111 can be operated by the operator. In that state, the check armbody 121 is apart from the dump lever 111 by the spring force of therelease spring 128. Thus, when the dump lever 111 is operated by theoperator (the dump cylinder 78 is in operation), the dump lever 111moves to a contact position with a regulation end 121 c or 121 d of thecheck arm body 121. Therefore, the position of the check arm body 121 isheld, between and a state that the lift lever 110 is locked in the liftchecking notch 121 a each pressure rollers 123, 124 is maintained.

When the dump lever 111 is operated by the operator, the regulation end121 c or 121 d of the check arm body 121 contacts with the dump lever111, and the movement of the check arm body 121 is blocked by the dumplever 111. Accordingly, even if the operator tries to operate the liftlever 110, the lift lever 110 cannot be operated because the lift lever110 is supported between the pressure rollers 123,124. In other words,in the state of FIG. 9 (the dump cylinder is in operation), where thedump lever 111 is operated, the operation of the lift lever 110 isinhibited by the check arm body 121.

On the other hand, as shown in FIG. 11, when the lift lever 110 isoperated in the ascending (descending)) direction by the operator (thelift cylinder 48 is in operation), the lift lever 110 pushes thepressure roller 123 (or pressure roller 124) while opposing the releasespring 128. Therefore, a position of the check arm body 121 is kept, andthe state that the dump checking notch 121 b is locked to the dump lever111 is maintained. In other words, in the state of FIG. 11 that the liftlever 110 is operated, an operation of the dump lever 111 is inhibitedby the check arm body 121. It is noted that when the mowed grassdischarge notch 120 a is separated from the lift lever 110, the operatorcan operate either the lift lever 110 or the dump lever 111alternatively.

Next referring to FIGS. 12 to 14, a mounting structure of a supportingleg body 132 as an outrigger preventing turnover of the traveling body 1is described. As shown in FIGS. 12 to 14, an outrigger support frame 133is welded to the lower end of the fixed mast 45. A middle part of a legbody base 135 of the supporting leg body 132 is supported by theoutrigger supporting frame 133 through the outrigger supporting shaft134. A top end of the leg body 136 of the supporting leg body 132 isconnected to the one end of the leg body base 135. A taking in/outoperation part 135 a of the other end of the leg body base 135 isextended to the lower part of the mast base 46 a of the movable mast 46.When the movable mast 46 is moved down, the mast base 46 a comes intocontact with the taking in/out operation part 135 a from above.

That is to say, during a mowing operation in which the movable mast 46is supported at the lowest position, the mast base 46 a contacts thetaking in/out operation part 135 a from above. Therefore, the end of theleg body 136 is lifted up to the retracted position far from the roadsurface. On the other hand, when the movable mast 46 is moved up, andthe grass collection box 30 is lifted up to a high place, the mast base46 a separates from the taking in/out operation part 135 a. Therefore,the supporting leg body 132 is rotated about the outrigger supportingshaft 134 by the self weight of the end part of the leg body 136. Thus,the end of the leg body 136 lands on the road surface.

In the above-described embodiment, the end of the leg body 136 isconfigured to land on the road surface by self weight of the end of theleg body 136 as the movable mast 46 is moved up, and also a spring maybe provided for rotating the supporting leg body 132. The supporting legbody 132 is rotated about the outrigger supporting shaft 134 by thespring (in the landing direction of the end of the leg body 136), andthe end part of the leg body 136 is oppressed to the road surface by thespring.

As shown in FIGS. 12 to 14, an outrigger locking mechanism 137 tosupport the supporting leg body 132 in a landing position is provided.The outrigger locking mechanism 137 has a ratchet gear 138 and a ratchetarm 140. The ratchet gear 138 is fitted to the outrigger supportingshaft 134. A ratchet pawl 139 for locking the ratchet gear 138 in anengaging or disengaging manner is integrally formed to with one end ofthe ratchet arm 140 lock the ratchet gear 138. The supporting leg body132 and the ratchet gear 138 are integrally about coupled each other.The supporting leg body 132 and the ratchet gear 138 integrally rotateabout the outrigger supporting shaft 134.

A lock fulcrum shaft 141 is disposed in the fixed mast 45. The middlepart of the ratchet arm 140 is rotatably fitted to the lock fulcrumshaft 141. A contracting roller 143 is supported to the other end of theratchet arm 140 through the roller shaft 142. A ratchet spring 144 isconnected between the fixed mast 45 and the ratchet arm 140. The ratchetpawl 139 is engaged with the ratchet gear 138 by the ratchet spring 144.

In the configuration described above, as shown in FIG. 12, while themovable mast 46 is supported at the lowest position, and the grasscollection box 30 is supported at a collecting position in the rear ofthe traveling body 1 (i.e., during a mowing operation in which themovable mast 46 is supported at the lowest position), the mast base 46 acontacts the taking in/out operation part 135 a of the supporting legbody 132. And the end of the leg body 136 of the supporting leg body 132is lifted up to a retracted position as shown in the solid line in FIG.12. In the case, the ratchet arm 140 also contacts with the mast base 46a through the contracting roller 143. The ratchet pawl 139 is supportedin a position which is separated from the ratchet gear 138 against theratchet spring 144. Therefore, the supporting leg body 132 is held in alower retracted position of the grass collection box 30.

As shown in FIG. 13, when the movable mast 46 is lifted from the lowestposition in FIG. 12, the mast base 46 a firstly separates from thetaking in/out operation part 135 a. Therefore, the end of the leg body136 drops by its weight to a landing position as shown in the solid linein FIG. 13, the end of the leg body 136 lands in the landing surface G(road surface). Secondly, when the movable mast 46 is further liftedfrom the landing position of the supporting leg body 132 of FIG. 13, themast base 46 a separates from the contracting roller 143 as shown inFIG. 14. Therefore, the ratchet arm 140 rotates into a position as shownin a solid line of FIG. 14 by the ratchet spring 144. And, the ratchetpawl 139 is locked to the ratchet gear 138 by the ratchet spring 144.Thus, the supporting leg body 132 is supported in such a way that thesupporting leg body 132 remains on the landing surface G (road surface).

That is to say, when the grass collection box 30 is lifted up in a highplace (the discharge position of mowed grass 89 shown in FIG. 6), bylocking the ratchet pawl 139 with the ratchet gear 138, the supportingleg body 132 is held in a landing position on the landing surface G. Inthe state, when the traveling body 1 inclines to the right or left, thetraveling body 1 is supported by the supporting leg body 132 on theinclined side. Accordingly, the traveling body 1 can be prevented frominclining to a turnover angle, and the turnover of traveling body 1 canbe prevented.

On the other hand, for example, when discharge of the mowed grass 89 inthe grass collection box 30 is completed, the grass collection box 30 islifted down in a position for collecting grass (position for mowing andcollecting grass shown in FIG. 3). When the grass collection box 30 islifted down in a position for collecting grass, the movable mast 46firstly moves down under a state of FIG. 14 that the ratchet pawl 139 isengaged with the ratchet gear 138. Then, as shown in FIG. 13, the mastbase 46 a comes into contact with the contracting roller 143. Therefore,the ratchet arm 140 rotates in a position shown in a solid line in FIG.13 against the ratchet spring 144. Accordingly, the ratchet pawl 139 isseparated from the ratchet gear 138.

Next, when the movable mast 46 further moves down from the disengagedposition of the ratchet pawl 139 of FIG. 13, (i.e., from the landingposition of the supporting leg body 132), the mast base 46 a contactsthe taking in/out operation part 135 a of the supporting leg body 132 asshown in FIG. 12. By dissension of the movable mast 46, the supportingleg body 132 comes to rotate about the outrigger supporting shaft 134.The end of the leg body 136 of the supporting leg body 132 is lifted upto the retracted position of the supporting leg body 132 as shown in asolid line in FIG. 12. That is to say, the supporting leg body 132 issupported in the retracted position that is higher than the bottom ofthe fixed mast 45. Therefore, when the traveling machine 1 is moved, andthe mowing operation is carried out, the supporting leg body 132 is heldbackward in an approximately horizontal manner in the vicinity of thebottom of the grass collection box 30. Accordingly, the supporting legbody 132 is prevented from colliding with the road surface, an obstacleetc. and from being damaged.

As is apparent from the above description and FIGS. 3 to 5, thefollowing are provided: a mower device 6 mounted on a traveling body 1having right and left rear wheels 6 (traveling part), a grass collectionbox 30 as a grass collector for collecting grass mowed by the mowerdevice 16, a discharge duct 29 for discharging the mowed grass from themower device 16 into the grass collection box 30, and a lift mechanism31 having right and left fixed masts 45 for supporting the grasscollection box 30 to the traveling body 1 to be lifted up and down. Itis configured that the mowed grass 89 in the grass collection box 30 isdischarged by lifting up the grass collection box 30 by the liftmechanism 31. The lift mechanism 31 is disposed in the lateral width ofthe grass collection box 30. The discharge duct 29 is disposed betweenthe right and left fixed masts 45. It is configured that the dischargeduct 29 and the grass collection box 30 are connected with the right andleft fixed masts 45. Therefore, the lift mechanism 31 can be disposed inthe right and left width of the right and left rear wheels 6, and thelift mechanism is prevented from colliding with a standing tree, afallen tree or an obstruct such as stones on the ground and from beingdamaged. Also, the right and left width of the grass collection box 30can be enlarged, and the volume thereof can be increased. In addition,between the right and left fixed masts 45, in the other words, in thevicinity of the approximate center of the right and left width of thetraveling body 1, the grass collection box 30 can be connected to themower device 16 through the discharge duct 29 extending approximatelylinearly. Accordingly, in comparison with the conventional structurethat the forcible transport mechanism to discharge mowed grass 89 fromthe mower device 16 to the grass collection box 30 is specially providedoutside the traveling body 1, the right and left width of the travelingbody 1 can be reduced, and the mowed grass 89 can be discharged from themower device 16 into the grass collection box 30 with a simpletransportation structure.

As is apparent from the above description and FIGS. 3 to 5, the liftmechanism 31 comprises right and left movable masts 46 liftablysupported with respect to right and left masts 45, a lift frame body 47liftably disposed with respect to the movable masts 46, and a liftcylinder 48 as a lift drive means for lifting up and down the lift framebody 47. The lift cylinder 48 is disposed on a base frame 50 connectedto the right and left fixed masts 45 above the discharge duct 29.Therefore, the base frame 50 can be used as both the supporting means ofthe right and left fixed masts 45 and the supporting means of the liftcylinder 48. Accordingly, the assembling structure of the right and leftfixed mast 45 and the lift cylinder 48 can simply be configured. Also,by the right and left fixed masts 45 and the base frame 50, both theright and left sides and the top side of the discharge duct 29 can beenclosed. Accordingly, the discharge duct 29 and the grass collectionbox 30 can simply be connected.

As is apparent from the above description and FIG. 3, FIG. 12, mastsupporting bodies 45 a of the right and left fixed masts 45 areconnected to the rear end of the body frame 3,4 of the traveling body 1.On the other hand, the right and left rear wheels 6 (traveling parts)are attached to the right and left axle frames 39 of the traveling body1. The bottom ends of the right and left fixed masts 45 are connected tothe right and left axle frames 39. Also, the right and left fixed masts45 are supported to the body frame 3,4 and the right and left axleframes 39. Therefore, the connection strength of the body frame 3,4 andthe right and left axle frames 39 can be improved by the right and leftfixed masts 45. Also, the connection strength of the body frame 3,4 andthe right and left fixed masts 45 can be improved by the right and leftaxle frames 39. That is to say, the right and left rear wheels 6 and thegrass collection box 30 can be supported with high rigidity.

As is apparent from the description and FIGS. 12 to 14, a supporting legbody 132 approaching to landing direction by upward movement of a grasscollection box 30 toward a position for discharging mowed grass isprovided. The leg supporting body 132 is moved apart in the direction ofthe ground (upside of the traveling road surface) by downward movementof the grass collection box 30 toward a position for collecting grass.Also, an outrigger locking mechanism 137, which locks the supporting legbody 132 in a landing position by upward movement of the grasscollection box 30 toward a position for discharging mowed grass, isprovided. The supporting leg body 132 and the outrigger lockingmechanism 137 are disposed at the bottom end of the right and left fixedmasts 45 respectively. Therefore, by the use of the right and left fixedmasts 45, the supporting leg body 132 can be supported with highrigidity in the vicinity of the road surface. That is to say, astructure to prevent the traveling body 1 from turning over can besimply configured with the supporting leg body 132 and the outriggerlocking mechanism 137.

Next referring to FIG. 15 and FIG. 16, a structure of the grasscollection box 30 of the present embodiment is described. As shown inFIG. 15, a cylinder opening/closing bearing body 145 is fixed to the topface frame 82 of the grass collection main body 76. A tube-shaped bossbody 147 is welded to a frame 146 of the cover 77. One end of theopening/closing operation arm 84 is welded to the boss body 147. Theboss body 147 is fitted to the pin-shaped opening/closing fulcrum shaft83 having a head 83 a. A retaining pin 148 is penetrated through theopening/closing fulcrum shaft 83 and the boss body 147. The top end ofthe opening/closing fulcrum shaft 83 is inserted in the opening at theend of the opening/closing bearing body 145. The right and left bossbodies 147 are respectively provided in the right and left rim frames146 of the cover 77.

That is to say, when the cover 77 is incorporated with the grasscollection main body 76 through the opening/closing bearing shaft 83,the right and left boss bodies 147 are penetrated insertably/extractablythrough the right and left opening/closing bearing shafts 83. At thesame time, the top ends of the right and left opening/closing fulcrumshafts 83 are inserted in the openings of the right and left ends of theopening/closing bearing body 145 respectively. Next, the right and leftopening/closing fulcrum shafts 83 are locked to the right and left bossbodies 147 by the right and left locking pin 148 respectively. The cover77 is connected to the grass collection main body 76 through theopening/closing fulcrum shafts 83 openably and closably. That is to say,the cover 77 can be connected to the grass collection main body 76without any tools.

On the other hand, when the cover 77 is removed from the grasscollection main body 76, the engagement between the right and left bossbodies 147 and the right and left opening/closing fulcrum shafts 83 isreleased by pulling out the right and left retaining pins 148 withoutany tools. Subsequently without using any tools, the right and leftopening/closing fulcrum shafts 83 are extracted from the openings at theends of the right and left opening/closing bearing bodies 145. That isto say, the cover 77 can be removed from the grass collection main body76 without using any tools.

In the above configuration, as shown in FIG. 16, for example, the grasscollection main body 76 can be used for collecting dust 149 or cut grassand tree etc. in a state where the cover 77 is removed from the grasscollection main body 76. That is to say, a big opening is formed in therear face of the grass collection main body 76 by removing the cover 77from the grass collection main body 76. From the opening in the rearface of the grass collection main body 76, the dust 149 or the prunedtrees and plants, which are collected by the operator, can be throwninto the grass collection main body 76. On the other hand, when thegrass collection main body 76 is full of the dust 149 or the trees andplants, the traveling body 1 moves to a place for dumping such as thecontainer 90 and the loading space of a truck. And like as describedabove, the grass collection main body 76 can be lifted up by theoperation of the lift cylinder 48, or be rotated backward by theoperation of the dump cylinder 78. The dust 149 or the trees and plantsin the grass collection main body 76 can be discharged to a dump placesuch as a container 90 or a back of a truck.

Next, referring to FIG. 17, in the lawn mower of the present embodiment,there will be described a control structure to automatically stop theengine 9 by a misoperation of the PTO clutch lever 18 by the operator.As shown in FIG. 17, a battery 22 for starting the engine 9 is provided.A PTO clutch engagement sensor 150 whose structure is an on-off switchtype is provided. The PTO clutch engagement sensor 150 detects the PTOclutch engagement operation of the above described PTO clutch lever 18(drive operation of the mower device 16). An engine stop solenoid 151 asan engine stop mechanism is provided. The PTO clutch engagement sensor150 and the engine stop solenoid 151 are connected to the battery 22 inseries. The supply of fuel from the fuel tank 20 to the engine 9 isstopped by the engine stop solenoid 151, and the engine 9 is alsostopped.

As shown in FIG. 17, the operator sensor 152 whose structure is anon-off switch type is provided. When the operator sits on the abovedescribed driver seat 15, the operator sensor 152 is turned off. The PTOclutch engagement sensor 150 and the engine stop solenoid 151 areconnected to the operator sensor 152 in series. Therefore, when nooperator sits on the driver seat 15, the operator sensor 152 remains on.That is to say, when the operator sits on the driver seat 15, theoperator sensor 152 turns off and the mower device 16 can be operated.On the other hand, when no operator sits on the driver seat 15, theoperator sensor 152 turns on, and the mower device 16 cannot beoperated. Also, the PTO clutch engagement sensor 150 turns on by a PTOclutch engagement operation of the PTO clutch lever 18. When the PTOclutch engagement sensor 150 turns on, the engine stop solenoid 151 isoperated and stops the engine 9 automatically.

As shown in FIG. 17, the parking lever 153 and the parking brake sensor154 whose structure is an on-off switch type are provided. By theparking lever 153, the above described brake pedal 13 is locked and heldlockably and unlockably in a braking position (a step-on position of thebrake pedal). When a locking operation of the brake pedal 13 by theparking lever 153 makes the parking brake turn on, the parking brakesensor 154 turns on. Also, the parking brake sensor 154 is connected tothe PTO clutch engagement sensor 150 and the engine stop solenoid 151 inseries. That is to say, the parking brake sensor 154 becomes on in astate where the brake pedal 13 is locked in the parking lever 153. Also,the engine 9 is stopped automatically by a PTO engagement operation ofthe PTO clutch lever 18. Accordingly, while the parking brake sensor 154is remained on during the operation of the parking brake, the mowerdevice 16 cannot be operated.

As shown in FIG. 17, the grass collection box lift-down sensor 155 whosestructure is an on-off switch type is provided. When the grasscollection box 30 described above is supported in a position forcollecting grass (at a lift-down position) at the rear of the travelingbody 1, the grass collection box lift-down sensor 155 turns on by thelift frame body 47. The grass collection box lifting down sensor 155 isconnected to the PTO clutch engagement sensor 150 and the engine stopsolenoid 151 in series. Accordingly, when the grass collection box 30 isnot supported in a position for collecting grass at the rear of thetraveling body 1, in other words, when the lift lever 110 is inoperation, the grass collection box lifting down sensor 155 turns on,and the mower device 16 cannot be operated. On the other hand, when thegrass collection box 30 is supported in a position for collecting grass(a mowing operation position) in the back of the traveling body 1, inother words, when the lift lever 110 is not in operation, the grasscollection box lifting down sensor 155 turns off, and the mower device16 can be operated.

As shown in FIG. 17, a lift lever operation sensor 156, which isactivated by lift-up and lift-down operations of the lift lever 110described above, is provided. The lift lever operation sensor 156 isconnected to the PTO clutch engagement sensor 150 and the engine stopsolenoid 151 in series. Accordingly, in a state where the PTO clutchlever 18 is operated to engage the PTO, for example, in a state wherethe mower device 16 is in operation when the lift lever 110 is operatedfor lifting up or down, the engine stop solenoid 151 is operated and theengine 9 is automatically stopped. Therefore, lifting up the grasscollection box 30 caused by a misoperation of the lift lever 110, duringthe operation of the mower device 16, can be prevented. That is to say,it is possible to prevent mowed grass from being scattered from theopening at the rear end of the discharge duct 29 to the outside of thegrass collection box 30.

On the other hand, FIG. 20 shows the embodiment that the engine 9 isstopped by the operation of the dump lever 111 instead of the lift lever110 in FIG. 17. As shown in FIG. 20, the grass collection box initialposition sensor 157 whose structure is an on-off switch type isprovided. When the grass collection box 30 described above is supportedin an upward position for collecting grass (the cover 77 is in a closingposition) above the lift frame body 47, the grass collection box initialposition sensor 157 is turned off by the grass collection box 30. Thegrass collection box initial position sensor 157 is connected to the PTOclutch engagement sensor 150 and the engine stop solenoid 151 in series.Accordingly, when the grass collection box 30 is not supported in aposition for collecting grass in the backward of the traveling body 1,for example, when the dump lever 111 is operated, the grass collectionbox initial position sensor 157 turns on. Therefore, the operation ofthe mower device 16 is prevented. That is to say, when the grasscollection box 30 is supported in a position for collecting grass (amowing operation position) above the lift frame body 47, in other words,when the dump lever 111 is not operated, the grass collection boxinitial position sensor 157 turns off, the mower device 16 can beoperated.

Also, as shown in FIG. 20, a dump lever operation sensor 158, turned onby an opening or closing operation of the dump lever 111, which isdescribed above, is provided. The dump lever operation sensor 158 isconnected to the PTO clutch engagement sensor 150 and the engine stopsolenoid 151 in series. Accordingly, when the mower device 16 isoperated by a PTO engagement operation of the PTO clutch lever 18, theengine stop solenoid 151 is actuated by the opening or closing operationof the dump lever 111, and thus automatically stops the engine 9. Thatis to say, during the operation of the mower device 16, misoperation ofthe dump lever 111 stops the engine 9 automatically. Therefore,scattering mowed grass from the opening at the rear end of the dischargeduct 29 to the outside of the grass collection box 30 can be prevented.

Next, a control of a grass collecting operation of the lawn mower in thepresent embodiment will be described. The control of the grasscollecting operation includes a mowed grass discharge control and anengine stop control. FIG. 18 is a functional block diagram of a controlmeans of the grass collection operation. As shown in FIG. 18, acontroller 160 for grass collecting operation, such as a microcomputer,is provided. The controller 160 includes a ROM which stores a controlprogram, and a RAM which stores various data. The controller 160 isconnected to the battery 22 through a key switch for applying power.

As shown in FIG. 18, various sensors for an input system and switchesare connected to the controller 160. That is to say, a brake sensor 161of a limit switch type, which turns on when the operator steps on thebrake pedal 13, is provided. A lift switch 162, which lifts up or downthe lift cylinder 48, is provided. A dump switch 163, which opens orcloses the dump cylinder 78, is provided. The brake sensor 161, the liftswitch 162, and the dump switch 163 are connected to the controller 160.Also, a PTO sensor 164 of an on-off switch type, which detects PTOengagement operation (drive of the mower device 16) of the PTO clutchlever 18, is provided. A seat sensor 165 of on-off switch type, which isoff operation when the operator sits on the seat 15, is provided. Aparking sensor 166 of an on-off switch type, which is activated by theengaging operation (in a state where a parking brake is in operation) ofthe brake pedal 13 by the parking lever 153, is provided. The PTO sensor164, the sheet sensor 165, and the parking sensor 166 are connected tothe controller 160. In addition, a grass collection sensor 167 of anon-off switch type, which is activated when the grass collection box 30is supported in a position for collecting mowed grass in the back of thetraveling body 1, is provided. The grass collection sensor 167 isconnected to the controller 160.

Furthermore, as shown in FIG. 18, various electromagnetic solenoids ofan output system are connected to the controller 160. That is to say, alift-up solenoid 107 a and a lift-down solenoid 107 b for a lift valve107 of an electromagnetic switch type, which lift up or down the liftcylinder 48, are provided. An opening solenoid 109 a and a closingsolenoid 109 b for a dump valve 109 of an electromagneticswitching-type, which open or close the dump cylinder 78, are provided.The engine stop solenoid 151 as an engine stop mechanism, which stopsthe engine 9 by canceling supply of fuel from the above-described fueltank 20 to the engine 9, is provided. The lift-up solenoid 107 a, thelift down solenoid 107 b, the opening solenoid 109 a, the closingsolenoid 109 b, and the engine stop solenoid 151 are connected to thecontroller 160.

Next, referring to a flow chart shown in FIG. 19, a discharge control ofthe mowed grass in the grass collection box 30 and a stop control of theengine 9 will be described. During the mowing operation of the grassetc. in the present embodiment, the operator determines whether thegrass collection box 30 is full of the mowed grass 89. When the mowedgrass 89 fills up the grass collection box 30, the operator moves thetraveling body 1 to a discharging place of the mowed grass 89 wherethere is the container 90 or a loading space of a truck. When the mowedgrass 89 in the grass collection box 30 is discharged into the container90 etc., it is determined whether or not the operator steps on the brakepedal 13 based on the detected results of the brake sensor 161 (S1).When the operator steps on the brake pedal 13 (S1: yes), by a lift-upoperation of the lift switch 162 by the operator (S2: yes), the liftcylinder 48 is actuated to lift up (S3). An opening operation of thedump switch 163 by the operator (S4: yes) actuates the dump cylinder 78to open (S5). That is to say, the grass collection box 30 at a positionfor collecting the mowed grass at the rear of the traveling body 1 islifted up to a position higher than the top face opening of thecontainer 90 by the lift-up operation of the lift switch 162. While thegrass collection main body 76 overturns backward by an opening operationof the dump switch 163, the cover 77 moves upward to the rear.Accordingly, the cover 77 opens, and mowed grass 89 in the grasscollection box 30 is discharged into the approximately center of the topface opening of container 90.

The operator determines whether or not the mowed grass 89 is dischargedfrom the grass collection box 30. When the mowed grass 89 is discharged,and the grass collection box 30 becomes empty, the closing operation ofthe dump switch 163 by the operator (S6: yes) actuates the dump cylinder78 to close (S7). In addition, the lift-down operation of the liftswitch 162 by the operator (S8: yes) actuates the lift cylinder 48 tolift down (S9). That is to say, when the discharge of the mowed grass 89from the grass collection box 30 is completed by the closing operationof the dump switch 163, the cover 77 moves downward to the front toclose while overturning of the grass collection main body 76 forwardly.Also, the lift-down operation of the lift switch 162 lifts down thegrass collection box 30, which is in a higher position than the top faceopening of the container 90, to a position for collecting grass at therear of the traveling body 1.

Accordingly, the mowing operation can be resumed by driving the mowerdevice 16. By resuming the mowing operation, the mowed grass 89 iscarried from the mower device 16 to the grass collection box 30 again,and the mowed grass 89 is collected in the grass collection box 30.

Accordingly, only when the operator steps on the brake pedal 13, thelift cylinder 48 is actuated by the operation of the lift switch 162, orthe dump cylinder 78 is actuated by the operation of the dump switch163. The lift cylinder 48 and the damp cylinder 78 do not operateconcurrently, that is, one of them is prevented from operating while theother is in operation. For example. Even if both the lift switch 162 andthe damp switch 163 are operated approximately at the same time by theoperator, or even if either the lift switch 162 or the damp switch 163is operated while the other has been operated, the lift cylinder 48 (orthe dump cylinder 78) is actuated based on the operation of the liftswitch 162 (or of the dump switch 163) which has been operated inadvance. That is to say, while the lift cylinder 48 is operating, thedump cylinder 78 is not even with the wrong operation of the dump switch163. Also, while the dump cylinder 78 is operating, the lift cylinder 48is not actuated even with the wrong operation of the lift switch 162.

On the other hand, in the above steps, when the operator performs thePTO engagement operation of the PTO clutch lever 18 (S13: yes), theengine stop solenoid 151 is actuated, and the engine 9 is forciblystopped (S14) under at least one of the following conditions: a statewhere the brake pedal 13 is not depressed by the operator (S1: no); astate where the operator is not seated on the seat 15, and thus the seatsensor 165 is off (S10: no); a state (a parking brake state) where thebrake pedal 13 is locked in a brake actuating position by the parkinglever 153 (S11: yes); or a state where the grass collection box 30 isnot supported in a position for collecting grass at the rear of thetraveling body 1 (S12: no).

That is to say, the mower device 16 is prevented from operating in thecase that no operator sits on the driver seat 15, that the parking brakeis on (the rear wheels are in a braked condition), or that the grasscollection box 30 is supported in a position other than that forcollecting grass at the rear of the traveling body 1.

Also, the brake mechanism 168 for braking the rear wheels 6 (or frontwheels 5) is connected to the above-described controller 160. The brakemechanism 168 is comprised of an electric brake motor (not shown), or ahydraulic brake cylinder and an electromagnetic brake valve etc. Whenthe lift cylinder 48 is actuated by the operation of the above describedlift lever 110 or the lift switch 162, the brake mechanism 168 isconfigured to be actuated approximately concurrently with the operationof the above-described lift lever 110 or the lift switch 162. Therefore,the rear wheels 6 are braked automatically by the operation of the liftlever 110 or the lift switch 162. That is to say, when the lift cylinder48 is operated to lift up and down the grass collection box 30, even ifa foot of the operator moves away from the brake pedal 13, or theoperator forgets to stepping on the brake pedal 13, braking of the rearwheels 6 prevents the traveling body 1 from moving.

Accordingly, while the traveling body 1 is kept in an approximatelyconstant place, the mowed grass 89 in the grass collection box 30 can bedischarged into the container 90, etc.

As is apparent from the above description and FIGS. 11 to 13, after thesupporting leg body 132 approaches (advances to) a landing direction bythe lift-up operation of the grass collection box 30, an additionallift-up operation of the grass collection box 30 makes the outriggerlocking mechanism 137 engage with the supporting leg body 132.Accordingly, while the supporting leg body 132 moves from a position forretracting that is apart from the landing surface G to a position forlanding, it is possible to prevent the supporting leg body 132 frombeing locked by the outrigger locking mechanism 137. After the outriggerlocking mechanism 137 locks the support leg body 132 in a landingposition, the grass collection box 30 can be lifted up. Also, after theoutrigger locking mechanism 137 is released from the supporting leg body132 by the lift-down operation of the grass collection box 30, anadditional lift-down operation of the grass collection box 30 makes thesupporting leg body 132 move apart from (retract from) the landingsurface G. Therefore, even if the grass collection box 30 is lifted downbefore unlocking the supporting body 132 in a landing position isunlocked, the supporting leg body 132 is not retracted in the directionseparate from the landing surface G. That is to say, even if thesupporting leg body 132 is retracted in association with the lift-downoperation of the grass collection box 30, it is possible to prevent thesupporting leg body 132, etc. from being damaged. Also, it can beprevented that the operator forgets to unlock the supporting leg body132. The mowing operation for the grass 89, etc. can be resumed aftercertainly returning the supporting leg body 132 to a retracting positionwhere the supporting leg body 132 is away from the landing surface G.

As is apparent from the above description and FIG. 3, FIG. 5, the liftcylinder 48 and the movable masts 46 are coupled to each other throughthe lift wires 58, 59 and the triple pulley 66 as a first double speedmechanism. The movable masts 46 and the lift frame bodies 47 are coupledto each other through the lift-up wires 74 and the lift-up pulleys 75 asa second double speed mechanism. The lift frame bodies 47 and the grasscollection box 30 are lifted up and down with respect to the movablemasts 46 by the up-and-down movement of the movable masts 46 withrespect to the fixed masts 45 by the lift cylinder 48. Therefore, theelevation length of the movable masts 46 can simply be twice as long asthat of the lift cylinder 48, and the elevation length of the lift frame47 can simply be twice as long as that of the movable masts 46. That isto say, the elevation length (lifting length amount) of the grasscollection box 30 (the lift frame body 47) can simply be four times aslong as that of the lift cylinder 48. Therefore, even if the elevationlength of the grass collection box 30 can be large and the grasscollection box can be lifted up highly, the lift cylinder 48 is simplyconfigured by, for example, an inexpensive short-stroke, light-weighthydraulic cylinder. When the grass collection box 30 is lifted down, themovable masts 46 can be retracted and lowered. That is to say, theheight of the fixed masts 45 and the movable masts 46 can becompactly-supported at the rear of the traveling body 1 so as not toblock the operator is view (backward view of the traveling body) whenthe traveling machine body 1 is driven backward.

As is apparent from the above description and FIG. 1, FIG. 9, and FIG.12, the grass collection box 30 (grass collector) is supported to belifted up and down through the lift cylinder 48 (lift drive means) totraveling body 1. The grass collection box 30 is rotatably supportedthrough the dump cylinder 78 (dump drive means). The brake pedal 13(brake operation body) braking the rear wheels 6 (traveling parts) ofthe traveling body 1, the lift lever 110 or the lift switch 162 (liftingoperation body) operating the lift cylinder 48, and the dump lever 111or dump switch 163 (rotating operation body) operating the dump cylinder78 are provided. The locking arm body 120 or the controller 160(permission control means), which permits the operation of the liftlever 110 (lift switch 162) and that of the dump lever 111 (dump switch163) by detecting the braking operation of the brake pedal 13, areprovided. Therefore, when the operator forcibly brake the rear wheels 6,the lift cylinder 48 or the dump cylinder 78 can be operatedrespectively. That is to say, during a mowing operation, even if thelift lever 110 (lift switch 162) or the dump lever 111 (dump switch 163)is wrongly operated, the wrong operation of the lift cylinder 48 or thedump cylinder 78 can be reduced. The mowed grass in the grass collectionbox 30 can be easily prevented from being discharged to a place otherthan a predetermined place.

As is apparent from the above description, d FIG. 9, and FIG. 12, thecheck arm body 121 or the controller 160 (check control means) isprovided. The check arm body 121 or the controller 160 restricts theoperation of either the lift lever 110 (lift switch 162) or the dumplever 111 (dump switch 163) by the operation of the other. Therefore, ifthe operator brakes the rear wheels forcibly, the lifting operation orrolling operation of the grass collection box 30 can selectively beperformed. That is to say, in a state where the traveling body 1 iscertainly stopped, the discharging operation of the mowed grass 89 inthe grass collector 30 is performed according to the predeterminedprocedure, and thus the turnover of the lawn mower can simply beprevented. Accordingly, weight saving of the lawn mower can provide areduction in manufacturing cost, and the increase in volume of the grasscollector 30 can improve the operability of mowing.

As is apparent from the above description, FIG. 1, FIG. 17, FIG. 18, andFIG. 19, the engine stop solenoid 151 is provided as an engine stopmechanism for stopping the engine 9 mounted on the traveling body 1. ThePTO clutch lever 18 as the PTO operation body for driving or stoppingthe mower device 16 is provided. In addition, the PTO clutch lever 18for driving the mower device 16, the PTO clutch sensor 150 or the PTOsensor 164 as the PTO engagement detecting means for detecting theoperation of the PTO clutch lever 18, the rear wheels 6 as the travelingpart of the traveling body 1, the parking lever 153 as the parking brakeholding the rear wheels 6 in a braked state, and the parking brakesensor 154 or the parking sensor 166 as the parking brake detectingmeans for detecting the operation of the parking brake 153 are provided.During the on-operation of the parking lever 153, by driving the mowerdevice 16 of the PTO clutch lever 18, the engine stop solenoid 151 isoperated. Therefore, the engine 9 can be stopped by the misoperation ofthe PTO clutch lever 18. That is to say, the improper driving of themower device 16 due to the misoperation by the operator can simply beprevented. Drivability or operability of mowing by the operator can beimproved.

The operator sensor 152 or the seat sensor 165 as the sitting detectingmeans for detecting that the operator sits on the driver seat 15 of thetraveling body 1 is provided. The engine stop solenoid 151 is operatedin at least one of the following cases: in the case that the parkinglever 153 is on-operated during the operation of the mower device 16;and in the case that the operator leaves the driver seat 15. Inaddition, the grass collection box lift-down sensor 155 or the grasscollection sensor 167 as the grass collection detecting means fordetecting the grass collection box 30 supported in a position forcollecting grass of the traveling body 1 is provided. In a state wherethe grass collection box 30 is supported at a position of the travelingbody 1 other than the position for collecting grass, the engine stopsolenoid 151 is operated by the drive operation of the mower device 16of the PTO clutch lever 18. Also, the lift lever 110 or the lift switch162 as a lift operation body for lifting up and down the grasscollection box 30, and the lift lever operation sensor 156 or thecontroller 160 as the lift detecting means for detecting at least eitheror both of the lift-up operation and the lift-down operation of the liftlever 110 or the lift switch 162, are provided. During the driving ofthe mower device 16, the engine stop solenoid 151 is actuated by thelift-up or lift-down operation of the lift lever 110 or the lift switch162.

As is apparent from the above description, FIG. 1, FIG. 3, and FIG. 5,the hydraulic lift cylinder 48 as the lift drive means having the pistonrod 55 advancing upward is provided. The hydraulic lift cylinder 48 isdisposed between the right and left fixed masts 45. Both the ends of theright and left lift wires 58, 59 as a mast traction body are connectedwith the traveling body 1 and the movable masts 46. The triple pulley 66as the tip guide pulley is disposed at the top end of the piston rod 55.The right and left lift wires 58,59 are provided in a stretched statethrough the triple pulley 66. Both the ends of the lift-up wires 74 asthe lift wire bodies are connected with the traveling body 1 and thelift frame body 47. The lift-up pulleys 75 as the movable guide pulleyare disposed at the upper end of the movable mast 46. The lift-up wires74 are provided in a stretched state through the lift-up pulleys 75.Accordingly, the lift frame body 47 can be lifted up toward the upperend of the movable mast 46 projecting from the upper end of the fixedmast 45. Therefore, when the mowed grass 89 is discharged, the grasscollection box 30 can be lifted up to an extremely high position. On theother hand, the movable mast 46 and the lift frame body 47 can be lifteddown within the height range of the fixed mast 45. Therefore, during themowing operation, in which the grass collection box 30 is lowered, theoverall body height can be lowered. Also, the hydraulic pressurestructure of the lift mechanism 31 for lifting up and down the grasscollection box 30 can simply be configured by providing a singlehydraulic lift cylinder 48. It is not necessary to provide the right andleft hydraulic cylinders in both right and left sides of the grasscollection box 30 as in a conventional manner.

In the above embodiment, the right and left lift wires 58, 59 areprovided as mast traction bodies, and the lift-up wire 74 is provided asa lift traction body. However, instead of the lift wires 58, 59 or thelift up wire 74, the mast traction body or the lift wire body may bemade of chain. In the case of forming the lift wires 58, 59 or thelift-up wire 74 with chain, a triple sprocket instead of the triplepulley 66 as a tip guide wheel and a sprocket instead of lift up pulley75 as movable guide wheels may be provided.

As is apparent from the above description, FIG. 3, FIG. 15, and FIG. 16,the grass collection box 30 is comprised of the grass collection mainbody 76 disposed in the lift mechanism 31 and the cover 77 disposed inthe back of the grass collection main body 76 to be openable andclosable. The bottom rear end of the grass collection main body 76 iscoupled to the rear end of the lift frame 47 projecting backward fromthe movable mast 46 by the dump fulcrum shaft 72. The grass collectionmain body 76 is configured to rotate backward about the dump fulcrumshaft 72. On the other hand, the upper front end of the cover 77 iscoupled to the upper rear end of the grass collection main body 76through the opening/closing fulcrum shaft 83 with a pin structure whichis detachable by a single operation. The cover 77 is configured torotate upward to the rear about the opening/closing fulcrum shaft 83.Also, the cover 77 is configured to be removed from the grass collectionmain body 76 by removing the opening/closing fulcrum shaft 83 from thegrass collection main body 76 coupled to the cover 77. Therefore, thecover 77 can easily be separated from the grass collection main body 76only by removing the opening/closing fulcrum shaft 83 from the grasscollection main body 76 without any tools. For example, the grasscollection main body 76 separated from the cover 77 can easily be usedfor dust collection, etc. for dumping branches of trees and dust, etc.in the container 90 and the like.

1. A lawn mower, comprising: a mower device mounted on a traveling bodyhaving right and left traveling parts; a grass collector for collectinggrass mowed by the mower device; a discharge duct for discharging themowed grass from the mower device into the grass collector; and a liftmechanism having right and left fixed masts for supporting the grasscollector to the traveling body to be lifted up and down; the liftmechanism being configured to lift up the grass collector and dischargethe mowed grass in the grass collector, wherein the lift mechanism isdisposed within a width right and left direction of the grass collector,the discharge duct being disposed between the right and left fixedmasts, and the grass collector being connected to the discharge duct ina position between the right and left fixed masts, wherein the liftmechanism has right and left movable masts supported to the right andleft fixed masts to be lifted up and down, a lift frame body disposed tothe movable masts to be lifted up and down, and a lift drive means forlifting up and down the lift frame body, wherein the lift drive means isdisposed on a base frame coupled to the right and left fixed masts abovethe discharge duct.
 2. (canceled)
 3. The lawn mower according to claim1, wherein the lawn mower is configured such that the lift drive meansand the movable masts are coupled to each other by a first double speedmechanism, that the movable masts and the lift frame body are coupled toeach other by a second double speed mechanism, and that the movablemasts are lifted up and down with respect to the fixed masts by the liftdrive, thereby the lift frame body and the grass collector are lifted upand down with respect to the movable masts.
 4. The lawn mower accordingto claim 1, wherein mast supporting bodies of the right and left fixedmasts are coupled to a rear end of a body frame of the traveling bodywhile bottom ends of the right and left fixed masts are coupled to rightand left axle frames of the traveling body for attaching right and lefttraveling parts.
 5. The lawn mower according to claim 1, comprising: asupporting leg body that approaches in a landing direction by upwardmovement of the grass collector to a position for discharging the mowedgrass and gets away from the ground by downward movement of the grasscollector to a position for collecting the grass; and a lockingmechanism that locks the supporting leg body in a landing position bythe upward movement of the grass collector to the position fordischarging the mowed grass; wherein the supporting leg body and thelocking mechanism are disposed at the bottom ends of the right and leftfixed masts.
 6. The lawn mower according to claim 5, wherein the lockingmechanism is configured to lock the supporting leg body by furtherupward movement of the grass collector after the supporting leg bodyapproaches in a landing direction by the upward movement of the grasscollector, and the supporting leg body is configured to get away from alanding surface by further downward movement of the grass collectorafter the locking mechanism is removed from the supporting leg body bythe downward movement of the grass collector.
 7. The lawn moweraccording claim 1, comprising: the grass collector supported through thelift drive means to the traveling body to be lifted up and down androtatably supported to the traveling body through a dump drive means; abrake operation body for braking the traveling parts of the travelingbody; a lifting operation body for operating the lift drive means; and arolling operation body for operating the dump drive means, wherein apermission control means for detecting a braking operation of thebraking operation body and permitting each operation of the liftingoperation body and the rolling operation body is provided.
 8. The lawnmower according to claim 7, comprising a check control means in whichone operation of either the lifting operation body or rolling operationbody restricts the operation of the other.
 9. The lawn mower accordingto claim 1, comprising: an engine stop mechanism for stopping an enginemounted on the traveling body; a PTO operation body for operating todrive or stop the mower device; a PTO detection means for detecting anoperation of the PTO operation body in order to drive the mower device;and a parking brake detecting means for detecting an operation of aparking brake for keeping the traveling parts of the traveling body in abraked state, wherein the engine stop mechanism is configured to beactuated by a driving operation of the mower device of the PTO operationbody when operating the parking brake to be on.
 10. The lawn moweraccording to claim 1, comprising: a hydraulic lift cylinder, as the liftdrive means, having a piston rod that advances upward, the hydrauliclift cylinder being disposed between the right and left fixed masts,wherein both ends of mast traction bodies are coupled to the travelingbody and the movable masts, and the masts traction bodies are providedin a stretched state through tip guide pulleys disposed at a top end ofthe piston rod, and both ends of the lift traction bodies are coupled tothe traveling body and the lift frame body, the lift traction bodiesbeing provided in a stretched state through movable guide pulleysdisposed at top ends of the movable masts.
 11. The lawn mower accordingto claim 1, wherein the grass collector comprises a grass collectionmain body disposed in the lift mechanism and a cover disposed to beopenable and closable on a rear face side of the grass collection mainbody, wherein a bottom rear end of the grass collection main body iscoupled to the rear end of the lift frame body projecting backward fromthe movable masts by a dump fulcrum shaft, the grass collection mainbody being configured to rotate backward about the dump fulcrum shaft, atop front end of the cover is coupled to a top rear end of the grasscollection main body through a pin-structured opening/closing fulcrumshaft capable of being attached and removed by one-touch operation, thecover being configured to rotate upward to a rear about theopening/closing fulcrum shaft, and the cover is configured to be removedfrom the grass collection main body by removing the opening/closingfulcrum shaft from the grass collection main body coupled to the cover.